kernel/linux.git/Documentation/vm, branch v5.15.209

Documentation: fix a hugetlbfs reservation statement

2026-06-01T15:35:32+00:00

[ Upstream commit 7a197d346a44384a1a858a98ef03766840e561d4 ] Documentation/mm/hugetlbfs_reserv.rst has if (resv_needed <= (resv_huge_pages - free_huge_pages)) resv_huge_pages += resv_needed; which describes this code in gather_surplus_pages() needed = (h->resv_huge_pages + delta) - h->free_huge_pages; if (needed <= 0) { h->resv_huge_pages += delta; return 0; } which means if there are enough free hugepages to account for the new reservation, simply update the global reservation count without further action. But the description is backwards, it should be if (resv_needed <= (free_huge_pages - resv_huge_pages)) instead. Link: https://lkml.kernel.org/r/20260302201015.1824798-1-jane.chu@oracle.com Fixes: 70bc0dc578b3 ("Documentation: vm, add hugetlbfs reservation overview") Signed-off-by: Jane Chu Cc: David Hildenbrand Cc: Hillf Danton Cc: Jonathan Corbet Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Oscar Salvador Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

Merge branch 'akpm' (patches from Andrew)

2021-09-08T19:55:35+00:00

Merge more updates from Andrew Morton: "147 patches, based on 7d2a07b769330c34b4deabeed939325c77a7ec2f. Subsystems affected by this patch series: mm (memory-hotplug, rmap, ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan), alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib, checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig, selftests, ipc, and scripts" * emailed patches from Andrew Morton : (94 commits) scripts: check_extable: fix typo in user error message mm/workingset: correct kernel-doc notations ipc: replace costly bailout check in sysvipc_find_ipc() selftests/memfd: remove unused variable Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH configs: remove the obsolete CONFIG_INPUT_POLLDEV prctl: allow to setup brk for et_dyn executables pid: cleanup the stale comment mentioning pidmap_init(). kernel/fork.c: unexport get_{mm,task}_exe_file coredump: fix memleak in dump_vma_snapshot() fs/coredump.c: log if a core dump is aborted due to changed file permissions nilfs2: use refcount_dec_and_lock() to fix potential UAF nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group nilfs2: fix NULL pointer in nilfs_##name##_attr_release nilfs2: fix memory leak in nilfs_sysfs_create_device_group trap: cleanup trap_init() init: move usermodehelper_enable() to populate_rootfs() ...

Documentation: add documents for DAMON

2021-09-08T18:50:25+00:00

This commit adds documents for DAMON under `Documentation/admin-guide/mm/damon/` and `Documentation/vm/damon/`. Link: https://lkml.kernel.org/r/20210716081449.22187-11-sj38.park@gmail.com Signed-off-by: SeongJae Park Reviewed-by: Fernand Sieber Reviewed-by: Markus Boehme Cc: Alexander Shishkin Cc: Amit Shah Cc: Benjamin Herrenschmidt Cc: Brendan Higgins Cc: David Hildenbrand Cc: David Rientjes Cc: David Woodhouse Cc: Fan Du Cc: Greg Kroah-Hartman Cc: Greg Thelen Cc: Ingo Molnar Cc: Joe Perches Cc: Jonathan Cameron Cc: Jonathan Corbet Cc: Leonard Foerster Cc: Marco Elver Cc: Maximilian Heyne Cc: Mel Gorman Cc: Minchan Kim Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Rik van Riel Cc: Shakeel Butt Cc: Shuah Khan Cc: Steven Rostedt (VMware) Cc: Vladimir Davydov Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

doc: hwpoison: correct the support for hugepage

2021-09-03T16:58:15+00:00

The hwpoison support for huge page, both hugetlb and THP, has been in kernel for a while, the statement in document is obsolete, correct it. Link: https://lkml.kernel.org/r/20210819054116.266126-2-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Naoya Horiguchi Reviewed-by: David Hildenbrand Cc: Oscar Salvador Cc: David Mackey Cc: Jonathan Corbet Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2021-07-02T19:08:10+00:00

Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton : (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...

mm: device exclusive memory access

2021-07-01T18:06:03+00:00

Some devices require exclusive write access to shared virtual memory (SVM) ranges to perform atomic operations on that memory. This requires CPU page tables to be updated to deny access whilst atomic operations are occurring. In order to do this introduce a new swap entry type (SWP_DEVICE_EXCLUSIVE). When a SVM range needs to be marked for exclusive access by a device all page table mappings for the particular range are replaced with device exclusive swap entries. This causes any CPU access to the page to result in a fault. Faults are resovled by replacing the faulting entry with the original mapping. This results in MMU notifiers being called which a driver uses to update access permissions such as revoking atomic access. After notifiers have been called the device will no longer have exclusive access to the region. Walking of the page tables to find the target pages is handled by get_user_pages() rather than a direct page table walk. A direct page table walk similar to what migrate_vma_collect()/unmap() does could also have been utilised. However this resulted in more code similar in functionality to what get_user_pages() provides as page faulting is required to make the PTEs present and to break COW. [dan.carpenter@oracle.com: fix signedness bug in make_device_exclusive_range()] Link: https://lkml.kernel.org/r/YNIz5NVnZ5GiZ3u1@mwanda Link: https://lkml.kernel.org/r/20210616105937.23201-8-apopple@nvidia.com Signed-off-by: Alistair Popple Signed-off-by: Dan Carpenter Reviewed-by: Christoph Hellwig Cc: Ben Skeggs Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Peter Xu Cc: Ralph Campbell Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: rename migrate_pgmap_owner

2021-07-01T18:06:03+00:00

MMU notifier ranges have a migrate_pgmap_owner field which is used by drivers to store a pointer. This is subsequently used by the driver callback to filter MMU_NOTIFY_MIGRATE events. Other notifier event types can also benefit from this filtering, so rename the 'migrate_pgmap_owner' field to 'owner' and create a new notifier initialisation function to initialise this field. Link: https://lkml.kernel.org/r/20210616105937.23201-6-apopple@nvidia.com Signed-off-by: Alistair Popple Suggested-by: Peter Xu Reviewed-by: Peter Xu Cc: Ben Skeggs Cc: Christoph Hellwig Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Ralph Campbell Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/rmap: split try_to_munlock from try_to_unmap

2021-07-01T18:06:03+00:00

The behaviour of try_to_unmap_one() is difficult to follow because it performs different operations based on a fairly large set of flags used in different combinations. TTU_MUNLOCK is one such flag. However it is exclusively used by try_to_munlock() which specifies no other flags. Therefore rather than overload try_to_unmap_one() with unrelated behaviour split this out into it's own function and remove the flag. Link: https://lkml.kernel.org/r/20210616105937.23201-4-apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Ralph Campbell Reviewed-by: Christoph Hellwig Cc: Ben Skeggs Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Peter Xu Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2021-06-30T00:29:11+00:00

Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton : (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...

docs: remove description of DISCONTIGMEM

2021-06-29T17:53:55+00:00

Remove description of DISCONTIGMEM from the "Memory Models" document and update VM sysctl description so that it won't mention DISCONIGMEM. Link: https://lkml.kernel.org/r/20210608091316.3622-8-rppt@kernel.org Signed-off-by: Mike Rapoport Acked-by: Arnd Bergmann Reviewed-by: David Hildenbrand Cc: Geert Uytterhoeven Cc: Ivan Kokshaysky Cc: Jonathan Corbet Cc: Matt Turner Cc: Richard Henderson Cc: Vineet Gupta Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds